Generally, containers are box-shaped receptacles used to efficiently and economically transport cargos. The containers have different lengths and heights, although containers each having a length of 20 ft or 40 ft are commonly used.
Such containers are stacked on a specific facility, such as a container terminal. The container terminal is normally located in front of a harbor. A great number of containers are stacked on the container terminal, and are then loaded onto a container ship.
The containers may have different heights although they have the same length. For example, the containers may be classified into dry containers each having a length of 40 ft and a height of 2.4 m and high-cubic dry containers each having a length of 40 ft and a height of 2.7 m. Consequently, the difference in height between each dry container and each high-cubic dry container is 0.3 m.
FIG. 49 is a perspective view schematically showing a conventional container terminal.
As shown in FIG. 49, a container terminal 100 is located in front of a harbor, in which a container ship 200 is at anchor. Containers 300 are unloaded from the container ship 200 by means of gantry cranes 400, and are then transferred to a field container storage space 500 by means of trailers, where the containers 300 are stacked.
On the other hand, the containers 300 stacked on the field container storage space 500 or other containers 300 taken to the field container storage space 500 by means of trailers are moved to the gantry cranes 400, by means of which the containers 300 are loaded onto the container ship 200.
However, a great number of containers are transferred by means of the gantry cranes and the trailers so that the containers are loaded onto or unloaded from the container ship. As a result, the containers unloaded from the container ship or the containers loaded onto the container ship from the field container storage space may not be quickly handled.
Also, the containers are stacked on the field container storage space while the containers are not classified. As a result, the containers are not reasonably handled on the basis of the lengths of the containers and variance in time elapsed until containers are removed from the container terminal, whereby storage and removal of the containers are not smoothly achieved.
The trailers used to transfer the containers to the gantry cranes are ordinary transporting means, each of which is operated by an operator. However, the transporting means are not reasonably controlled nor smoothly managed. As a result, the containers are not smoothly loaded onto or unloaded from the container ship.
Also, the containers are not smoothly stored or transferred due to the above-mentioned problems. As a result, human and material resources are wasted while the container terminal is operated.
It is required that the container terminal have a large area sufficient to stack a great number of containers thereon. However, it is very difficult to obtain a site for the container terminal. Although a large-scale container terminal is provided, the containers are not efficiently stacked on the field container storage space of the container terminal.
Furthermore, the containers are stacked on the large-area field container storage space of the container terminal while being scattered, and the stored containers are kept away from the container ship. As a result, a great number of transport equipments and much manpower is necessary to transfer the containers to the container ship.